1. Field of the Invention
The present invention relates to a 6-axis force sensor structure using a force sensor and a method of measuring force and moment therewith. More particularly, the invention relates to a 6-axis force sensor structure which generates electric signals corresponding to forces of 3 axes and the moments of 3 axes using a uniaxial force sensor film having force sensor distribution and a cross-shaped press member and a method of measuring forces and moments of 6 axes using the 6-axis force sensor structure.
2. Background of the Related Art
Most conventional uniaxial/multiaxial load cells use a strain gauge. However, the manufacturing cost of the strain gauge is as high as more than $100 and mass production of the strain gauge is difficult to achieve because the strain gauge is manually manufactured.
Furthermore, the variance of manufactured load cells is considerably large and a resistance variation due to a force is very small, for example, 1 to 2Ω, to result in a small signal variation, and thus it requires high cost to manufacture a signal processing unit and the volume of the signal processing unit increases. For instance, the signal processing unit requires $1,000 for each axis, that is, a total of $3,000, to process forces and moments of 3 axes.
Due to the aforementioned shortcomings, the load cells are difficult of access although they have a variety of applications. Accordingly, a new uniaxial/multiaxial load cell that can be easily manufactured and mass-produced to replace the conventional uniaxial/multiaxial load cells is needed.
Recently, a force sensor has been manufactured using a sensing unit that combines a small pressure sensor and a pressure transfer liquid and gel instead of the strain gauge. However, the sensing unit is difficult to design and manufacture because the sensing unit must be sealed up. Furthermore, the force sensor cannot secure reliability when tension is applied thereto while the force sensor has reliability when compressed. Moreover, the force sensor is difficult to measure a moment although it can measure simple tension when using a liquid and gel. Accordingly, a sensing unit in the form of a membrane is required in order to improve durability against tension and compression. However, the sensitivity of the force sensor using the sensing unit in the form of a membrane decreases since the membranous sensing unit has a small variation within a small load range although it has a large variation within a large load range, and thus the force sensor using the membranous sensing unit is not suitable as a uniaxial/multiaxial force sensor. Accordingly, a new sensing unit that is robust to tension and compression and is easily combined with an external structure while reducing loss of force is needed in order to use a force sensor in the form of a film as a uniaxial/multiaxial force sensor.